Two Heads, One Body

Time magazine (March 25, '96) had an article about a six-year
old girl, or two six-year old girls rather, with two heads and
one body. They're like 2 totally different people with different
personalities and preferences. They have separate urges to eat,
sleep and go to the bathroom. What if anything does Judaism says
about such a situation. Is there any source in the Talmud that
talks about this? Would they be considered one person or two?

Dear Ephraim,

Ever hear the phrase, 'Nothing's new under the sun?'

The Talmud records an exchange in which Phlimo asked Rabbi Yehuda
HaNasi, "A person with two heads, upon which head does he
place the tefillin?" Rabbi Yehuda thought Phlimo
was merely jesting, when suddenly someone arrived and announced,
"My wife had a baby with two heads! How much must I give
for the redemption of the first-born?"

The Talmud concludes that the father must give double the normal
amount. The Torah says the firstborn must be redeemed at "five
sela'imper head." So here, where there are
two heads, the father must give ten sela'im.

From the above, you can't necessarily extrapolate to other cases,
because there are two opposite ways to understand it:

Since the father gives double, they must be considered two
people.

They are one person who simply pays extra for the extra head.

According to the Midrash, a two-headed man lived in the time of
King Solomon. He fathered six normal children and a seventh with
two heads like himself. When the father died, the son with two
heads came before King Solomon demanding a double share of the
inheritance. King Solomon covered one head and poured hot water
on the other. "Ouch!" both heads cried out. From this
King Solomon meant to show that genetically they are one, and
should be judged as one for inheritance purposes. The Talmud,
however, does not record this incident.

The Zohar records a tradition about the descendants of Cain, stating
that they were born with two heads.

Actual instances of conjoined twins are found in the works Sha'ar
HaShamayim (Ralbag 1547), Cheshek Shlomo (1773) and
Shvut Yaakov (Rabbi Yaakov Reisher of Prague, 1739) and
others.

The Shvut Yaakov himself saw twin boys, normal in all ways,
but whose heads were joined side by side. In such a case, he
writes, they are certainly separate people. He distinguishes
between this case and the case in the Talmud where the two heads
share one body.

There's really nothing new under the sun: Adam and Eve, says
the Talmud, were created as a single male/female being with two
faces. The subsequent creation of Eve was actually the splitting
of the male and female into two separate parts!